Adjustable spring assembly

Abstract

The present invention provides a suspension apparatus having a primary leaf spring and a secondary leaf spring. The primary leaf spring can have a pair of spaced-apart ends that are attached to a frame and the secondary leaf spring can have a pair of spaced-apart ends that are unattached to the frame. A movable block is also included, can be attached to the frame and is located proximate to one of the pair of unattached ends of the secondary leaf spring. The movable block is operable to move closer to and further away from the proximate unattached end of the secondary leaf spring.

1 . A suspension apparatus comprising:
 a frame;   a primary leaf spring and a secondary leaf spring;   said primary leaf spring having a pair of spaced-apart ends attached to said frame and said secondary leaf spring having a pair of spaced-apart ends unattached to said frame, said secondary leaf spring located between said primary leaf spring and said frame;   a movable block attached to said frame and proximate one of said pair of unattached ends of said secondary leaf spring, said movable block operable to be moved closer to and further away from said one unattached end and change a spring rate of said secondary leaf spring after a load has been applied to said frame and said secondary leaf spring has contacted said movable block.   
     
     
         2 . The suspension apparatus of  claim 1 , wherein said movable block is bolted to said frame through one of a plurality of apertures in said frame, said plurality of apertures located for said movable block to be bolted to said frame at a first position and a second position. 
     
     
         3 . The suspension apparatus of  claim 1 , further comprising a rotatable cam in contact with said movable block, said rotatable cam operable to rotate and move said movable block closer to and further away from said one unattached end of said secondary leaf spring. 
     
     
         4 . The suspension apparatus of  claim 1 , further comprising a mechanical screw in contact with said movable block, said mechanical screw operable to rotate and move said movable block closer to and further away from said one unattached end of said secondary leaf spring. 
     
     
         5 . The suspension apparatus of  claim 1 , further comprising an air bladder in contact with said movable block, said air bladder operable to expand, contract and move said movable block closer to and further away from said one unattached end of said secondary leaf spring. 
     
     
         6 . The suspension apparatus of  claim 1 , further comprising a stationary block attached to said frame proximate another of said pair of spaced apart unattached ends of said secondary leaf spring. 
     
     
         7 . The suspension apparatus of  claim 1 , wherein said movable block is a first movable block and further comprising a second movable block proximate another of said pair of spaced apart unattached ends of said secondary leaf spring, said second movable block operable to be moved closer to and further away from said another unattached end and change the spring rate of said secondary leaf spring after the load has been applied to said frame and said secondary leaf spring has contacted said first movable block and said second movable block. 
     
     
         8 . The suspension apparatus of  claim 7 , wherein said first movable block and second movable block can be moved closer to and further away from said one unattached end and said another attached end, respectively, using a movement mechanism selected from the group consisting of a bolt and aperture mechanism, a cam mechanism, a mechanical screw mechanism, an air bladder mechanism and combinations thereof. 
     
     
         9 . The suspension apparatus of  claim 8 , wherein said first movable block and said second movable block are both bolted to said frame with said bolt and aperture mechanism. 
     
     
         10 . The suspension apparatus of  claim 8 , wherein said first movable block and said second movable block both have said cam mechanism. 
     
     
         11 . The suspension apparatus of  claim 8 , wherein said first movable block and said second movable block both have said mechanical screw mechanism. 
     
     
         12 . The suspension apparatus of  claim 8 , wherein said first movable block and said second movable block both have said air bladder mechanism. 
     
     
         13 . A process for changing a spring rate for a suspension apparatus, the process comprising:
 providing a frame;   providing a primary leaf spring and a secondary leaf spring;   the primary leaf spring having a pair of spaced-apart ends attached to the frame and the secondary leaf spring having a pair of spaced-apart ends unattached to the frame, the secondary leaf spring located between the primary leaf spring and the frame;   providing a movable block attached to the frame and proximate one of the pair of unattached ends of the secondary leaf spring, the movable block operable to be moved closer to and further away from the proximate unattached end, the movable block having a first position and a second position;   providing a load onto the frame, the load compressing the primary leaf spring until the movable block contacts the proximate unattached end thereof, the secondary leaf spring having a first spring rate when the movable block is in the first position and a second spring rate when the movable block is in the second position.   
     
     
         14 . The process of  claim 13 , wherein the movable block is bolted to the frame through one of a plurality of apertures in the frame, the plurality of apertures located for the movable block to be attached to the frame at the first position and the second position. 
     
     
         15 . The process of  claim 13 , further including a rotatable cam in contact with the movable block, the rotatable cam operable to rotate and move the movable block between the first position and the second position. 
     
     
         16 . The process of  claim 13 , further including a mechanical screw in contact with the movable block, the mechanical screw operable to move the movable block between the first position and the second position. 
     
     
         17 . The process of  claim 13 , wherein the movable block has an air bladder that can expand and contract, the air bladder operable to move the movable block between the first position and the second position. 
     
     
         18 . The process of  claim 13 , further comprising a stationary block proximate another of the pair of spaced apart unattached ends of the secondary leaf spring. 
     
     
         19 . The process of  claim 13 , wherein the movable block is a first movable block and further including providing a second movable block proximate another of the pair of spaced apart unattached ends of the secondary leaf spring, the second movable block operable to move closer to and further away from the another unattached end. 
     
     
         20 . The process of  claim 19 , wherein the first movable block and the second movable block can be moved closer to and further away from the one unattached end and the another attached end of the secondary leaf spring, respectively, using a movement mechanism selected from the group consisting of a bolt and aperture mechanism, a cam mechanism, a mechanical screw mechanism, an air bladder mechanism and combinations thereof.